JPH02264305A - I/o device for programmable controller - Google Patents

Abstract

PURPOSE:To simplify input processing by inputting the signal for confirming that the switching operation of an input signal is finished when one of a control signal and a diagnostic signal is switched and inputted selectively. CONSTITUTION:When a sensor provided with a failure diagnosis is connected to an I/O device, a switch 11 is closed previously. Thus, when an input signal switching signal inputted through an FF 6 becomes L-level, the output of an inverter 74 becomes H-level, and the output of the multiplexer 3 is switched to diagnostic output. Simultaneously, the output of the inverter 75 becomes H-level, and a counter 78 is operated. A shift register 7 operated by a clock is connected to the counter 78, and after the lapse of prescribed time, a confirming signal is outputted through a buffer 79. This prescribed time is the time required for operation that the multiplexer 3 is operated after the input switching signal is inputted and the output is switched perfectly from the control signal to the diagnosis signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an I10 device of a programmable controller to which a sensor with fault diagnosis can be connected.

(Summary of the Invention) The present invention provides a method for selectively switching and inputting either a control signal or a diagnostic signal manually input from a sensor with a fault diagnosis to a 110 device of a programmable φ controller.
By inputting a confirmation signal to confirm that the input signal switching operation has been completed, input processing at the time of switching is made simple and reliable.

(Prior art and its problems) Conventionally, in a programmable controller I10 device to which a sensor with fault diagnosis can be connected, either the control signal or the diagnostic signal output from the sensor with fault diagnosis is controlled by a switching command from the CPU main body. When inputting signals by selectively switching between them, the signal acquisition timing after switching must be set in consideration of the time required for signal switching.

Therefore, it is necessary to configure a timer in the user program and recognize the input signal as a control signal or a diagnostic signal after the time has elapsed, and the user needs two timer instructions for one sensor with failure diagnosis. This has the disadvantage that the program structure becomes complicated.

(Object of the Invention) This invention was made to solve the above problems, and its purpose is to change the signal acquisition timing setting when switching the input from the connected sensor with fault diagnosis. An object of the present invention is to provide an easy-to-use programmable controller I10 device that eliminates the need to use timer instructions in a user program.

(Structure and Effects of the Invention) In order to achieve the above object, the present invention includes an interface circuit into which a control signal and a diagnostic signal outputted by a sensor with failure diagnosis are respectively input, and an interface circuit which receives both the above signals input into this interface circuit. Among them, there is a switching circuit that selectively switches and outputs a control signal as an input signal during normal operation and a diagnostic signal as an input signal during trouble diagnosis processing, and after a switching signal that instructs operation is input to this switching circuit,
The present invention is characterized by comprising a confirmation signal output circuit that outputs a confirmation signal indicating that the switching operation has been completed.

With this configuration, the I10 device of the programmable controller of the present invention can switch the input signal when selectively switching and inputting either the control signal or the diagnostic signal input from the sensor with fault diagnosis. Since a confirmation signal is input to confirm that the operation has been completed, input processing at the time of switching is simplified, and there is no need to use a timer instruction in the user program, resulting in improved usability.

(Example) Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an I10 device of a programmable controller according to an embodiment.

This I10 device has connectors 1. MPU (Central Processing Unit), which is the center of overall control5. and an input interface controlled by the MPU5 2. Multiplexer 3. Output interface 8. Buffer 4. Flip-flop 6, switching circuit 7. Communication interface consisting of R8-485 standard9. It is composed of a transcoder 10. FIG. 2 is a circuit diagram specifically showing the configuration of the switching circuit 7. As shown in FIG.

In the figure, switch 11 is switched depending on whether or not a sensor with failure diagnosis is connected to the I10 device, and is closed when the sensor with failure diagnosis is connected.

By closing the switch 11, the buffers 72 and 76 are turned on,
Buffers 73 and 79 are turned on, and flip-flop 6
The input signal switching signal input via the buffer 73
After passing through the inverter 74, the multiplexer 3
is input to the counter 78 via the inverter 75.
Add to the list.

An input signal consisting of 16 bits is input to the multiplexer 3 via the input interface 2 as shown in the n channel in FIG. , and only the most significant 16 bits are used as confirmation signals, and its output is connected to the buffer 76. Inputs from the sensor with failure diagnosis include a control signal that indicates what the sensor has detected, and a diagnostic signal that indicates whether or not the sensor itself is faulty.

Normally, an L level signal is applied to the multiplexer 3 from the inverter 74, and a control signal is selected from among the input signals and output to the buffer 4. Here, an L level signal is input to the flip-flop 6 as an input signal switching signal.
, the output of the inverter 74 is inverted to H level, and the output of the multiplexer 3 is switched to the diagnostic signal. At the same time, the input signal switching signal is inverted by the inverter 75 to become H level, and is input to the counter 78, causing the counter 78 to operate. A shift register 7 operated by a clock signal is connected to the counter 78, and a confirmation signal is outputted via a buffer 79 after a predetermined time has elapsed. This predetermined time is after the input signal switching signal is input.
This is the time required for the multiplexer 3 to operate and the output to be completely switched from the control signal to the diagnostic signal.

The input signal switching signal input via the flip-flop 6 is issued when executing the fault diagnosis process written in the user program, and after the input signal switching signal is output, the confirmation signal is input. A diagnostic signal is captured for the first time, and a determination is made as to whether or not the sensor with failure diagnosis is operating abnormally.

In addition, when the sensor with failure diagnosis is not connected to the I10 device, the switch 11 is opened and the buffers 72 and 76 are turned on.
Buffers 73 and 79 are turned off, and the signal input via flip-flop 6 passes through buffer 72 and reaches output interface 8 . In other words, when a sensor with failure diagnosis is not connected, or when a failure diagnosis process is not performed even if it is connected, the signal inputted through the flip-flop 6, which should originally be an input signal switching signal, is used as a normal output signal. At the same time, all 16 bits of the input signal can be used as input for sensors, etc., making efficient use of the I10 device and providing expandability.

FIG. 3 is an I10 memory map of this device, in which a confirmation signal is assigned to the most significant bit of the n channels for input signals, and an input signal switching signal is assigned to the most significant bit of the (n+1) channel for output signals. These most significant bits are used as normal input/output signals as described above when failure diagnosis processing is not performed.

As described above, in this embodiment, when switching the control signal from the connected sensor with failure diagnosis to the diagnostic signal and inputting it, the confirmation signal is output after the time required for switching has elapsed. If the content of the diagnostic signal is read after confirming the output of the confirmation signal, the user program does not require extensive use of timers, which simplifies program creation.

In addition, if you do not connect a sensor with failure diagnosis, switch 1.
1 and output the switching signal as a normal output signal, it is possible to realize an easy-to-use and efficient I10 device.

In addition, in the above embodiment, the circuit configuration is such that the confirmation signal is output only when switching from a control signal to a diagnostic signal, but the confirmation signal is also output when switching from a diagnostic signal to a control signal. It can also be configured.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an I10 device according to an embodiment of the present invention, FIG. 2 is a circuit diagram specifically showing the configuration of a switching circuit, and FIG. 3 is an I10 memory map of this device. 1... Connector 2... Input interface 3... Multiplexer 4... Buffer 5... MPU 6... Flip-flop 7... Switching circuit 8... Output interface 9... For communication Interface 10...Transcoder 11...Switch 71...Inverter 72...Buffer 73...Buffer 74...Inverter 75...Inverter 76...Buffer 77...Shift register 78... ...Counter 79...Buffer

Claims (1)

[Scope of Claims] 1. An interface circuit that inputs the control signal and the diagnostic signal outputted by the sensor with failure diagnosis, respectively; Of the two signals inputted to this interface circuit, during normal operation, the control signal is used for failure diagnosis. During processing, there is a switching circuit that selectively switches and outputs each diagnostic signal as an input signal, and after a switching signal that instructs the operation is input to this switching circuit,
An I/O device for a programmable controller, comprising: a confirmation signal output circuit that outputs a confirmation signal indicating that a switching operation has been completed.